Conventional extension cords are provided at one of their end portions with a male plug having prongs and at the other end portion with a socket having bores adapted to receive prongs from another male plug.
In certain instances, a plurality of extension cords must be joined end to end to form a chain which will allow the user to obtain a desirable extension cord length. In these situations, any type of pulling action or other movement imparted on a section of the chain is susceptible of retracting the male prongs of a given extension cord from the corresponding bores into which they were initially inserted.
Once, one or more prongs are partially retracted from the corresponding bores into which they were initially inserted, not only is the flow of electrical current to the appropriate location interrupted but the situation also creates a potential serious hazard since the prongs become exposed to the environment and there is a possibility of short-circuiting, sparks, etc. . . .
A number of structures have been proposed to minimize such risks. U.S. Pat. No. 2,753,534 and 2,945,203 both disclose connectors that employ a threaded sleeve to connect two elements together in order to prevent the plug and socket members from separating. Such structures, however, present a major drawback. Even if the prongs and bores of these connectors were compatible with the corresponding prongs and bores of conventional plugs and sockets, the described socket elements could not be independently connected to any conventional plug and the described plug member could not be connected to any conventional socket. In both patents, the described structure comprise a rotatable, internally threaded sleeve on the plug side of the connector and a corresponding annular externally threaded ring on the socket side of the connector.
Both the sleeves and the rings form a physical obstacle which prevent insertion into conventional plugs and sockets. The threaded sleeve is laterally fixed to the plug side to physically and electrically protect the prongs.
Accordingly, the present invention provides a plug and socket arrangement which has an integral connector for retaining both the plug and the socket together.
The connector is slidingly mounted on one of the elements of the combination thus allowing either the novel plug or socket to be used independently with commercially available components. This advantage could prove to be particularly useful when one of the two parts of the novel combination fails to operate properly and one must rely on available conventional plug or sockets.